Distributor for ignition system



Sept. 11, 1956 w, SMITs 2,762,877

DISTRIBUTOR FOR IGNITION SYSTEM Filed June 22, 1954 1N VEN TOR. 077;?5.675 Mfrs United States Patent DISTRIBUTOR FOR IGNITION SYSTEM WytzeBeye Smits, Voorburg,

Smitsvonk, N. V., P y

Netherlands, assignor to Leidschendam, Netherlands, a com- Thisinvention relates to a distributor, and more particularly to adistributor specifically designed for use with an ignition systememploying low voltage spark plugs operating on condenser discharges.

Some of the problems connected with the operation of distributors whichhave been used heretofore are pointed out in the inventors Patent No.2,587,780 issued March 4, 1952, for Electrical Ignition System. In thatpatent a distributor is described which is provided with a plurality ofouter fixed contacts and an inner rotating contact. It can be readilyappreciated that both the rotating contact and fixed contacts tend towear away and as they Wear away, the timing of the ignition system isdelayed. The width of the contacts determines the length of time thecontacts may be used without replacement, but it is also true that thewider the contacts, the greater the timing may be delayed. Accordingly,one of the problems in connection with the use of prior art distributorshas been to strike a balance as to the width of the contacts so as topermit relatively infrequent replacement and yet not produce too large atime delay.

Another of the ditficulties encountered in prior art distributorsrelates to the heat produced by the sparking between the rotatingcontact and the fixed contacts. It can be seen that in the rotatingcontact a great deal more heat is produced than in the fixed contacts,since sparks are created on the rotating contact many times more than onindividual fixed contacts. The heat created by this sparking is noteasily dissipated and consequently, the gap between the rotating andfixed contacts is not maintained at the correct dimensions.

in addition, it has been customary to support the rotating contact armon a spindle between two spaced bearings and it has frequently occurredthat these bearings become slightly displaced and the gap between therotating and fixed contacts is varied.

The present invention seeks to overcome all of the foregoingdisadvantages of prior art distributors and yet provides a distributorwhich is practical, relatively inexpensive to manufacture and of simpleconstruction. A plurality of fixed contacts are provided on an innerinsulated block, and these fixed contacts are connected with respectivespark plugs. An arm is provided which rotates on an elongated sleevedisposed on a central spindle. This arm is provided with a contact whichengages the fixed contacts as the arm rotates about the spindle. Acondenser is connected with the contact on the rotating arm and thecondenser is charged during the time the rotating contact is travelingbetween the fixed contacts and discharges When the rotating contact issufiiciently close to a fixed contact for the charge to jump the gap anddischarge across the spark plug.

The distributor described herein is intended for use primarily with lowvoltage spark plugs such as disclosed in the inventors Patent No.2,125,035 issued July 26, 1938 for Electric Ignition System and SparkingPlug for Internal Combustion Engines. The essential feature of suchspark plugs is that they employ relatively low voltages and provide aspark which in etfect creeps across the surface of the plug. Thiscreeping discharge is attained by providing a semi-conductor between theelectrodes of the plug. One of the principal advantages of such sparkplugs is that they are capable of operating on a condenser discharge andthat a distributor can be used to sequentially connect the ignitioncondenser with individual spark plugs.

By virtue of the novel arrangement of parts of the presently describeddistributor, more exact timing is possible with the same width ofcontacts as is used in prior art distributors. This is occasioned by thefact that the radius of the rotating contact arm is greater and,consequently, the angle through which the rotating contact ann movesfrom the initial sparking position to the sparking position when thecontact members are worn down is correspondingly smaller. As is pointedout in the inventors Patent No. 2,587,780, previously referred to, it isthis angle which determines the possible variation in the timing. inthis manner, inventor has decreased the variation in timing withoutaffecting the life of the contact points.

The present invention also permits the rotating contact arm to be bettercooled so that the heat created by sparking does not expand the metalcontact member and vary the size of the spark gap. The rotating arm ismore eificiently cooled since it is traveling at a larger linearvelocity and since it is mounted on the outside of the rest of thedistributor parts and receives a greater circulation of air.

The rotating arm of the presently described distributor is supported inbearings along its entire length to insure that the correct sparkingdistance is maintained between the fixed contacts and the rotatingcontact at all times.

The present invention provides a distributor which, if desired, may beprovided with wider contacts and correspondingly increased life withoutany sacrifice in the exactness of timing over the prior artdistributors. This may be accomplished by reason of the fact that theradius of the rotating arm is greater and the angle between the initinlsparking point and the sparking position when the contacts are worn downis substantially smaller. Thus, it is possible to widen the contacts andbring the above referred-to angle to the same value as with prior artdistributors. in this manner, the distributor may be used for a longerperiod of time without replacing the contacts.

A primary object of this invention is to provide a distributor whichgives greater exactness in timing with no sacrifice in the life of thedistributor.

A further object of this invention is to provide a distributor in whichthe gap between the fixed contacts and the rotating contact is moreaccurately maintained at the correct dimension.

Other objects and many of the attendant advantages of this inventionwill become apparent in the light of this specification when consideredin connection with the accompanying drawing wherein:

Fig. l is a diagrammatic plan view of a distributor constructed inaccordance with the present invention and Fig. 2 is a sectional view ofthe distributor shown in Fig. l.

in the drawings, 1 is a rotor spindle, the upper end of which isprovided with a contact In connected to a con denser 2 which is suitablygrounded. Secured to the rotor spindle 1 in any suitable manner is aU-shaped member having outwardly extending arms 3 and 5. Suitablysecured on the outer end of arm 3 is a contact 4, and mounted on theouter end of arm 5 is a weight 6 which counter-balances the weight ofthe contact 4.

An insulating block 7 which is fixed with respect to the rotatableU-shaped arm is provided with a plurality of equidistantly spacedstationary contacts 8. These contact members are connected withindividual spark plugs 9 as clearly shown in Fig. 1.

The presently described distributor operates in the following manner.The rotor spindle 1 rotates and rotates the U-shaped arm and contact 4about the insulating block 7 provided with the stationary contacts. Thecondenser 2 is charged by a circuit (not shown) during the period oftime that the rotating arm is traveling between contacts 8. When contact4 approaches a stationary contact 8 the charge on condenser 2 willdischarge through a spark plug 9. By providing the rotating arm on theoutside of the fixed contacts, the radius of the rotating arm isincreased and more exact timing is attained. Furthermore, since therotor spindle is supported throughout its length in insulating block 7,the maintenance of the proper spark gap dimensions between rotatingcontact 4 and the stationary contacts is assured.

Obviously, many modifications and variations of the present inventionmay be employed without departing from the essentials thereof. What isclaimed as new and desired to be secured by Letters Patent is:

1. In a distributor to distribute a point to point spark in a lowvoltage ignition system, a rotatable spindle, an insulating blockjournaled on said spindle, a plurality of stationary contacts fixed insaid insulating block, an angular arm mounted on said spindle and havinga portion extending adjacent the outer periphery of said insulatingblock, and a contact member of substantially the same width as saidstationary contacts mounted on said arm for rotation therewith and forcooperation with said stationary contacts, said contact member beingspaced from said stationary contacts by predetermined spark gap.

2. A distributor according to claim 1 wherein a second angular armhaving a counterweight mounted thereon is attached to said spindlediametrically opposite said first angular arm.

3. in a distributor according to claim 2, wherein said angular arms areattached to said spindle below the insulating block.

References Cited in the file of this patent UNITED STATES PATENTS547,683 Rowland Oct. 8, 1895 1,030,432 Royce June 25, 1912, 1,062,738Schmidt May 27, 1913 1,558,304 Smulski Oct. 20, 1925 2,321,805Fritzinger June 15, 1943 2,587,780 Smits Mar. 4, 1952

